Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:33:38: error: invalid conversion from ‘long int (*)(const void*, const void*)’ to ‘__compar_fn_t {aka int (*)(const void*, const void*)}’ [-fpermissive] qsort (a, n, sizeof(long), compare); ^ In file included from /usr/local/include/c++/4.8.0/cstdlib:72:0, from /usr/local/include/c++/4.8.0/bits/stl_algo.h:59, from /usr/local/include/c++/4.8.0/algorithm:62, from user.cpp:4: /usr/include/stdlib.h:756:13: error: initializing argument 4 of ‘void qsort(void*, size_t, size_t, __compar_fn_t)’ [-fpermissive] extern void qsort (void *__base, size_t __nmemb, size_t __size, ^ user.cpp:23:23: warning: unused variable ‘x’ [-Wunused-variable] long long n, m,i,x,y; ^ user.cpp:23:25: warning: unused variable ‘y’ [-Wunused-variable] long long n, m,i,x,y; ^